* {
    padding: 0;
    margin: 0;
}

body {
    position: relative;
    height: 100vh;
    background: rgb(172, 172, 172);
}

.box {
    position: absolute;
    top: 200px;
    left: 150px;
    width: 400px;
    height: 300px;
    background-image: url(./5.gif);
    background-size: contain;
    background-repeat: no-repeat;
}

.mask {
    position: absolute;
    top: 0;
    left: 0;
    width: 200px;
    height: 200px;
    background-color: white;
    opacity: .4;
    display: none;
}

.big {
    position: absolute;
    top: 128px;
    left: 650px;
    width: 400px;
    height: 400px;
    background: url(./5.gif);
    background-size: 800px 600px;
    background-repeat: no-repeat;
    display: none;
}